Boris warned about sending political messages to his 59,000 Twitter followers

"The matter was referred to the GLA panel for dealing with complaints, who concluded last month that the mayor "could have been seen" to have been breaching a clause in the code of conduct governing elected members, "as it appeared on the evidence presented that the mayor of London was using GLA resources in seeking to affect party political support"."

With nearly 59,000 followers Boris Johnson is by far the biggest Conservative representative on Twitter.

David Cameron (famously) does not Tweet for fear of looking a "Tw*t"! The most newsy Twitterer inside CCHQ is Head of Press, Henry Macrory.

The Prime Minister's wife, Sarah Brown, is the biggest Labour star on Twitter. At just over one million followers, she has much more 'Twitterpower' than Boris. With Downing Street emblazoned all over her site, however, she will be limited in her use of Twitter to back her husband.